I suspect most magic items won't require attunement. The article talks of powerful ones, and ones that are a significant part of a character's identity - Excalibur for King Arthur would seem like an example. Drizzt is specifically brought up in the article, and has a lot more than three magic items, but it's defensible that the only one that's really significant to him is that Figurine he has. So that's the one he should be attuned to.
I can't really agree there. His swords are fairly serious items with names and history and gone on about a great deal too. His panther is so extreme that it's almost more than a magic item - more like an actual NPC. Personally I would expect him to be attuned to all those things.
Attunement seems pretty sensible at first glance, and I hope it gives minor mechanical effects which are cool but increase breadth of abilities, not power, and forces people to make some actual choices.
My concern, though, is that D&D will go down the route it has so often, historically, and use attunement as another opportunity to show Primary Magic Users > Everyone Else. The Fighter and other characters, historically at least (and in the versions of 5E we've seen) benefit from and even "need" magic items vastly more than Wizards or their ilk, because they're far more reliant on mechanical bonuses, and on items in general. A Wizard will probably see genuine choice on what to attune. For a Fighter, though, they are probably looking at a weapon and armour as bare necessity, if attunement gives any kind of mechanical advantage. Which leaves them only one slot for actual interesting stuff.
The simple solution, of course, would be to never give mechanical bonuses which directly increase the power of weapons/armour/etc. Unfortunately, I will be very surprised if, in actuality, this is the case. I expect we will see a lot of stuff which basically ends up as "+1 to hit if attuned" (which is a huge deal). Because the Fighter (etc.) has his weapons and armour factor constantly in combat, and linearly increase his power, he needs to attune them. Because the Wizard in 5E doesn't need any such thing (unlike 4E, where he did), he will still be able to pick and choose.
Hopefully it won't turn out this way, of course. I'd like to be wrong on this prediction, but it really does seem to be the way the wind is blowing on 5E (to me).
Threads worked decently in Earthdawn, note, because pretty much everyone needed them equally.
EDIT - An alternate solution, if it turns out that this is the case, is to simply allow Fighters etc. to attune more magical items (there are a thousand "lore" justifications one could use for this, if desired). For example, if a Fighter "needs" two magical items attuned for practical mechanical reasons (assuming linear power increase bonuses appear from attunement), he could be allowed to attune 5 items overall.